Sir Keir Starmer has refused to back the European Union in a trade war after Donald Trump threatened to slap tariffs on exports from the bloc.

The Prime Minister said that choosing between Brussels or Washington was not an “either/or” question given the United Kingdom’s relations with both.

It came after Mr Trump warned that Britain had been “out of line” in its trade with the US and described the situation with the EU as “an atrocity”.

The US president said that Brussels could expect to be hit with trade levies “pretty soon”, sparking market turmoil on the Continent.

On Monday, Sir Keir said that it was “early days” in discussions over Britain also falling foul of trade measures from Washington.

After a meeting with Mark Rutte, Nato’s secretary-general, at the alliance’s headquarters in Brussels, the Prime Minister avoided picking sides in the spiralling transatlantic spat.

“In relation to the US and the EU, or Europe more generally, if you look at our vital interests, it’s really important we work with both and don’t see it as either/or,” he told a news conference on Monday.

“When it comes to trade, we have a huge amount of trade between the US and UK, and that’s why it’s important that I act in the national interest, the best interest of the UK as we stay resolute in saying it’s important we work with both sets of partners.”